Proliferating normal bone marrow cells do stain for Ki-67 antigen

Area of Science:

• Hematology
• Immunohistochemistry
• Cell Biology

Background:

• Previous studies reported low proliferation-associated antigen scores in normal human bone marrow.
• The Ki-67 antibody has been used to assess cell proliferation.

Purpose of the Study:

• To investigate normal human bone marrow cell proliferation using a new antibody.
• To re-evaluate proliferation markers in bone marrow using MIB 1 and formalin fixation.

Main Methods:

• Used MIB 1 antibody, a Ki-67 equivalent.
• Employed formalin fixation for bone marrow smears and trephine biopsies.
• Analyzed staining percentages in normal bone marrow cells.

Main Results:

• Reported 52.8% +/- 9.2 SD of normal bone marrow (BM) cells stained positive for MIB 1.
• Observed staining in late forms of maturing blood cells (metamyelocytes, megakaryocytes) in cytokine-treated marrows.

Conclusions:

• Normal human bone marrow exhibits a higher proliferation rate than previously suggested by Ki-67 studies.
• MIB 1 antibody with formalin fixation provides a more sensitive assessment of bone marrow cell proliferation.